Jeremy Clarkson is never going to be elected president of the World Wide Fund for Nature. And he was unlikely to make a celebrity appearance at the Live Earth concert yesterday. The presenter of Top Gear is already infamous for his sceptical take on green politics, but even he may have gone too far this time.

Environmentalists are enraged this weekend as word has emerged from Africa that the macho television presenter and his BBC crew have just been filmed driving around one of the world's few untouched wildernesses for a new series of the show.

In a sequence that will dent the BBC's ecological profile, the Top Gear team is to be shown crossing the protected Makgadikgadi salt pans in Botswana in an assortment of vehicles believed to include 4x4s, quad bikes and pick-up trucks as part of one of the off-road 'challenges' set up for the programme.

The salt pans are the largest in the world, covering 16,000 sq km, and are the relic of a vast ancient lake. In the rainy season the area becomes a breeding ground for endangered birds, including two species of flamingo. Conservation experts complained yesterday that the top layer of soil in the pans is extremely fragile and tracks left by Clarkson and his crew will remain for decades. They are even more upset by the impact that showing the footage on television will have for this sensitive region.

'This is a big Boy's Own adventure, but it's doing nothing for the place at all,' said Mary Rice, head of campaigns at the Environmental Investigation Agency. 'After this programme is aired, are we going to see hordes of boy racers descending on the area wanting to do the same?'

While the BBC has a growing international reputation as a force for good among environmentalists and climate change experts because of its heavy investment in research and in shows such as Saving The Planet and Springwatch, it is behaving hypocritically, say conservationists, if it continues to promote careless self-indulgence in a popular show such as Top Gear. Clarkson once famously said: 'There will be no tree, leaf, cloud, lawn, peat bog or environmental precious place that I won't drive over.'

'The BBC is trying to have it both ways,' said Rice. 'It's spending a fortune and clearing its schedules to promote Live Earth and save the environment, but at the same time it's sending people down to potentially trash one of the last pristine wildernesses on Earth with a fleet of motor vehicles, all for the sake of a good picture.'

A spokeswoman for the BBC admitted that the location used for this sequence of Top Gear was held in a delicate ecological balance, but she said every effort was made to minimise the effects on the environment.

'We employed several experts on the salt pans with environmental expertise who advised us on where we could and couldn't go, and ensured that we never went near any conservation areas,' said the spokeswoman.

None the less, several local safari guides, including David Dugmore, have strong reservations about the visit from Top Gear. Dugmore, who runs a tented safari camp and takes paying guests out to experience the almost lunar landscape, told The Observer that the BBC crew had used respected guides, but said that local people were still concerned about the 'spin-off'.

'The thing that worries me is the viewers and public that are going to go out to the lakes, and we will end up with every Tom, Dick and Harry that comes up, with vehicles and quad bikes, which will absolutely spoil the place,' he said.

Not every guide in Botswana was worried about Top Gear's visit, however. Peter Perlstein, who runs a local helicopter company and helped with filming on one day, said the pans were already a popular 'self-drive destination' and 70-80 vehicles might visit in a weekend: 'Hundreds of tourists drive all over the plain on a regular basis, so I can't see how their vehicles could have made a difference,' he said.

Jeremy's Clangers

· On global warming: 'I'm not a scientist, but I read enough scientific literature to know the whole global warming theory is bonkers. A complete fairy story.'

· On the BBC: 'I'm bored by the BBC's hysterical climate change reporting. Global warming started out as a lie and became an industry.'

· On the British countryside: on Top Gear last year, Clarkson angered environmentalists when he drove a Land Rover up Ben Tongue in the Scottish Highlands. He has been criticised for abandoning a Bentley on a Devon beach.

· On Rebecca Lush, the protester who put a pie in his face in 2005: 'Millions of people enjoy Top Gear and they are more important than some bird with a pre-menstrual problem.'